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Bees do what?

August 2014

The positive risk assessments of GM grain cropshave been based on the premise that, because
they areadapted for wind pollination
and largely self-pollinating, there is little concern about gene-flow from them
into other crops.

Grain crop have a flower structure which aids
wind-pollination, and their pollen is not well adapted for carriage by
insects.Tests have shown that the
amounts of pollen carried by winddecrease exponentially with distance from the crop, reaching zero within
a few meters.Also, pollen is
short-lived.The risk of gene pollution
arising from GM grain crops has, therefore, been considered effectively zero.

However, a recently published study has challenged this
view.

Although insects are major pollinators of many fruit and
vegetable crops, their presence in wind-pollinated plants has never been
factored in.A team of Chinese and
American scientists took a long hard look at insect activity in rice crops to
see what impact it might have.

The study has several strands, all of which yielded quite
surprising data.

A two-year nationwide
survey in Chinese rice fields identified over 500 species of insects visiting
the flowers. These included 40 species
of bees and 28 species of hover-flies all of which collect large amounts of
pollen.

Honeybees were the
most abundant species foundin 26% of
locations.They therefore received a
more detailed study.The bees came from
colonies up to half a kilometer away from the field, appearing as soon as the
flowers opened and continuing to forage there until the flowers withered.Individuals were found to be carrying 400 or
more pollen grains by the end of each trip.

Investigation of one
colony located 500 meters from the rice field indicated that 81% of the pollen
arriving there was viable.

A field-cage experiment showed that gene flow from GM to
conventional rice with or without the presence of bees was below 1%.However, the bees were responsible for a
significant, up to 25-fold, increase in flow.In the big outdoors however, bees introduce a non-random effect into
gene flow.Because they concentrate
their attention to areas where flowers are at the optimum stage of maturity,
the gene flow from their activity can result in pockets of“extremely large” (10%) levels of hybrid seed
formation.

It was noted that other studies have recorded honeybees
foraging over 13 kilometers from their hive, and have found that pollen grains
can be further spread by nest-mate mixing.

OUR COMMENT

This study highlights, once again, the level of
assumption-based 'science' which routinely permeates the risk assessment of GM
crops.

The question of GM pollen-contaminated honey is another very
thorny one.A small study in Mexico,
whose exports of honey to the EU alone were worth $54 million in 2011, found GM
pollen in honey after the first year GM soya was planted there.This clearly contradicts industry claims that
bees do not visit soya because the flowers are self-pollinated.Note that the Mexican courts have now
cancelled Monsanto's permit to grow GM soya there.

Co-existence of GM rice, soya and similar grain crops with
non-GM is clearly impossible unless flowering times can be guaranteed to be entirely
separate in time.But then, what's a
farmer expected to do if unusual weather alters his crop's flowering time?Plough it under?Annihilate all the insect pollinators in his
field?

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About us

Formerly known as the Scottish Consumers Association for Natural Food, Pro-natural Food Scotland was formed in 1996 by a group of concerned people in Glasgow, Scotland. We are funded entirely by donation and run by volunteers. We network with, and support, all like-minded groups and individuals. Our objective is to empower by raising awareness.